The Arctic Mediterranean Sea is located north of the Greenland–Scotland Ridge and allows warm water from lower latitudes to penetrate beyond the Polar Circle. The northward flowing water is cooled in the Norwegian Sea and its density increases. In the Arctic Ocean the high river runoff and the net precipitation lead to a density decrease in the ...

The Arctic Mediterranean Sea is located north of the Greenland–Scotland Ridge and allows warm water from lower latitudes to penetrate beyond the Polar Circle. The northward flowing water is cooled in the Norwegian Sea and its density increases. In the Arctic Ocean the high river runoff and the net precipitation lead to a density decrease in the surface layers and heat loss at the sea surface results in the formation and maintenance of a permanent sea-ice cover. Brine ejected by freezing creates dense waters on the Arctic Ocean shelves, which sink as convecting boundary plumes into the deeper layers. In the Eurasian Basin the water column primarily reflects the interaction between the two inflows from the Norwegian Sea: through Fram Strait and over the Barents and Kara Sea and their different transformation histories. In the Canadian Basin the water transformations are dominated by the boundary convection, which makes the Canadian Basin water column different from that of the Eurasian Basin already at levels shallower than the now known sill depth of the Lomonosov Ridge. In the Greenland Sea deep-reaching, open-ocean convection occurs, partly rehomo-genising the water column. The waters entering the Arctic Mediterranean are thus transformed partly into a low salinity, cold upper layer, partly into cold, dense deep waters which all re-cross the Greenland–Scotland Ridge. The dense waters sink into the deep North Atlantic to supply the North Atlantic Deep Water. A reduction of the deep convection in the Greenland Sea has recently been inferred and the Greenland Sea deep water renewal presently occurs by advection of deep waters from the Arctic Ocean. Observed changes in the temperature and salinity of the Greenland Sea Deep Water are used to estimate the vertical diffusion coefficient in the deep layers and the renewal time of the deep salinity maximum layer, which originates from deep water outflow from the Eurasian Basin through Fram Strait. A weaker convection in the Greenland Sea is found to influence primarily the deep water circulation internal to the Arctic Mediterranean. The supply of dense overflow water from the upper layers in the Greenland Sea and from the other sources is not expected to be reduced. Minimize

A fast iterative algorithm is proposed for the construction and the learning of a neural net achieving a classification task, with an input layer, one intermediate layer, and an output layer The network is able to learn an arbitrary training set. The algorithm does not depend on a special learning scheme (e.g., the couplings can be determined by...

A fast iterative algorithm is proposed for the construction and the learning of a neural net achieving a classification task, with an input layer, one intermediate layer, and an output layer The network is able to learn an arbitrary training set. The algorithm does not depend on a special learning scheme (e.g., the couplings can be determined by modified Hebbian prescriptions or by more complex learning procedures). During the process the intermediate units are constructed systematically by collecting the patterns into smaller subsets. For simplicity, we consider only the case of one output neuron, but actually this restriction is not necessary. Minimize

We have developed and realized a concept which is very well suited for a quick recognition of highly correlated patterns. For a hetero-associative memory we used a minimal optimized output code (index memory). We constructed a tree structure in which the assignment of indices has been optimized by simulated annealing. Thus the algorithm for opti...

We have developed and realized a concept which is very well suited for a quick recognition of highly correlated patterns. For a hetero-associative memory we used a minimal optimized output code (index memory). We constructed a tree structure in which the assignment of indices has been optimized by simulated annealing. Thus the algorithm for optimal stability of the learned patterns works most effectively. Special care was taken of recognizing « real » objects, e.g. scanned letters. Here the characteristic noise is very anisotropic. We have slightly modified the minimal overlap strategy of Krauth and Mezard [1] by training with this specific noise, and could improve the performance of our network. In order to get insight into the network and its behaviour we used a measure called constructivity which shows clearly the anisotropic effects. We trained a network to recognize a scanned text and to produce the associated text file. Due to the architecture of the network many processes can be treated in parallel. Therefore we used transputers for the implementation. Minimize

Bacteriorhodopsin (BR) is folded into a bundle of seven alpha-helices which is embedded in the cellular membrane of Halobacterium salinarium; these helices are connected by short extra-membrane loops, three on the cytoplasmic side and three on the outside. Oligonucleotide-directed insertion or replacement mutagenesis was used to integrate the C-...

Bacteriorhodopsin (BR) is folded into a bundle of seven alpha-helices which is embedded in the cellular membrane of Halobacterium salinarium; these helices are connected by short extra-membrane loops, three on the cytoplasmic side and three on the outside. Oligonucleotide-directed insertion or replacement mutagenesis was used to integrate the C-terminal sequence (13 amino acids long) of Sendai virus L-protein individually into each of the six helix-connecting loops. The altered gene products were obtained by expression of the mutant genes in either Escherichia coli or Schizosaccharomyces pombe and were used to reconstitute BR in proteoliposomes. In four cases (altered loops B/C, C/D, D/E or E/F), the mutant BRs were found to be fully functional as judged by light-driven proton pumping and photocycle kinetics. Within the four functional BR variants, recognition of the viral epitope by a monoclonal antibody is restricted to modified loops B/C and E/F. Immunogold staining of S.pombe cells producing either of the two latter BR variants shows that the protein is distributed among various cellular membranes but is not present in mitochondrial membranes. Sequence alteration of loop A/B or F/G resulted in loss of function, most plausibly due to a folding defect of the respective proteins. These results on the one hand document differences in structural importance of the various BR extra-membrane loops and on the other hand open the door to the construction of multifunctional membrane proteins via loop replacement mutagenesis of BR. Minimize

Neurofibromatosis 1 (NF1) is a tumour suppressor gene syndrome characterized by multiple cutaneous and plexiform neurofibromas. Focal osseous abnormalities, short stature, and decreased bone mineral density are also frequent in people with NF1. We measured serum 25-hydroxyvitamin D concentrations in 55 patients with NF1 and 58 healthy controls, ...

Neurofibromatosis 1 (NF1) is a tumour suppressor gene syndrome characterized by multiple cutaneous and plexiform neurofibromas. Focal osseous abnormalities, short stature, and decreased bone mineral density are also frequent in people with NF1. We measured serum 25-hydroxyvitamin D concentrations in 55 patients with NF1 and 58 healthy controls, and correlated the findings in the patients with NF1 with their estimated number of dermal neurofibromas. Geometric mean (SD) serum 25-hydroxyvitamin D concentration was 14.0 (1.6) ng/mL among the patients with NF1 compared with 31.4 (1.7) ng/mL among healthy controls (p<<0.0001). The serum vitamin D concentration and number of dermal neurofibromas reported by patients with NF1 were inversely correlated (Spearman’s ρ = −0.572, p<0.00001). The occurrence of low serum vitamin D concentrations in people with NF1, especially those with many dermal neurofibromas, may provide new pathogenic insights and have important therapeutic implications. Minimize

Neurofibromatosis 1 (NF1) is a tumour suppressor gene syndrome characterized by multiple cutaneous and plexiform neurofibromas. Focal osseous abnormalities, short stature, and decreased bone mineral density are also frequent in people with NF1. We measured serum 25‐hydroxyvitamin D concentrations in 55 patients with NF1 and 58 healthy controls, ...

Neurofibromatosis 1 (NF1) is a tumour suppressor gene syndrome characterized by multiple cutaneous and plexiform neurofibromas. Focal osseous abnormalities, short stature, and decreased bone mineral density are also frequent in people with NF1. We measured serum 25‐hydroxyvitamin D concentrations in 55 patients with NF1 and 58 healthy controls, and correlated the findings in the patients with NF1 with their estimated number of dermal neurofibromas. Geometric mean (SD) serum 25‐hydroxyvitamin D concentration was 14.0 (1.6) ng/mL among the patients with NF1 compared with 31.4 (1.7) ng/mL among healthy controls (p<<0.0001). The serum vitamin D concentration and number of dermal neurofibromas reported by patients with NF1 were inversely correlated (Spearman's ρ = −0.572, p<0.00001). The occurrence of low serum vitamin D concentrations in people with NF1, especially those with many dermal neurofibromas, may provide new pathogenic insights and have important therapeutic implications. Minimize